Woven articles



June 25, 1963 4 R. BLEILER ETAL 3,095,017

WOVEN ARTICLES Filed July 14, 1959 3 Sheets-Sheet 3 INVENTORS RICHARDBLEILER ROBERT M. HARRIES BY N RMAN C. JECKEL SAMUEL H. LA PORT GW ,M+

ATTORN VS fluoroethylene resin).

3,095,017 WOVEN ARTICLES Richard Bleiler and Robert M. Harries,Allentown, Pa, Norman C. Jeckel, Glens Falls, N.Y., and Samuel H.Lamport, Shaker Heights, Ghio, assignors to United States Catheter &Instrument Corporation, Glens Falls, N.Y., a corporation of New YorkFiled July 14, 1959, fier. No. 827,127 11 Claims. (Cl. 139-387) Thisinvention relates to improvements in the weaving of articles and is moreparticularly concerned with weaving liquid-impervious bifurcated tubesto be used as blood vessel grafts or other prosthesis.

The recent expansion of vascular surgery has increased the need forblood vessel substitutes, particularly arteries, and artery banks havebeen established for this purpose. Homografts (natural blood vessels)have been used to a certain extent but such use is greatly restricted bylimited supply, time and expense that is connected therewith. Since thesupply of homografts is limited, it is extremely difiicult to match thevarieties of size and shapes of blood vessels that may be necessaryduring surgery, the size of which may not be known prior to surgicalentry.

The normal blood vessel is an extremely tough and resilient organ whichmust be flexible and elastic but at the same time strong andnon-collapsible. The varied properties of the normal blood vessel isparticularly emphasized at the joints, having an extensive range ofmovement, 'e.g., the hip joint between the legs and the primary bodytrunk. In fact, one of the common but difficult locations for bloodvessel substitution has been the aortic bifurcation where the aortadivides into the iliac arteries to supply each leg.

It was only natural that attempts be made to secure synthetic bloodvessels to be used on a surgical basis. Many materials have beensuggested but nylon (polyhexamethylene adipamide) appears to be thefirst to have been utilized on a commercial basis. Since that time othermaterials have been developed or suggested, including Dacron (Duponttrademark for polyethylene glycol terephthalate), Orlon (Duponttrademark for polyacrylonitrile) and Teflon (Dupont trademark for tetra-Various other materials have been suggested, but these have been theleading ones.

Of these presently used materials, it has been found that Teflon causesthe least tissue reactivity, retains greater strength over a period oftime, heals more rapidly as a graft, exhibits a lower rate of thrombosisand occlusion and causes formation of a thinner fibrous layer in theinternal bore, than any of the other materials. Thus, at the presenttime, Teflon is the preferred material.

There is a present and growing demand in vascular surgery for Wovenbifurcated tubes that are impervious to blood and particularly for aY-tube to be used at the aortic bifurcation into the iliac arteries. Notonly must the weaving be dense enough to prevent leakage but thejunction or crotch must be both strong and leakproof, as there isgreater stress normally applied at this point.

It is an object of this invention to provide woven bifurcated tubeshaving common warp threads through- .out the single tube portion and thebifurcated portions.

It is also an object of this invention to provide tubing of thecharacter described in a Y-shape which is densely ice woven andimpermeable to blood for use as blood vessel prosthesis.

It is a further object of this invention to provide tubing of thecharacter described which is leakproof and reinforced at the bifurcationjunction.

We have found a tube may be continuously woven from common warp yarnshaving a single tube portion which bifurcates into two portions and thatthe junction or point of bifurcation may be reinforced if desired. Theentire operation may be carried out continuously on narrow fabric looms,i.e., weaving the single tube portion, then weaving the two bifurcatedportions and then returning to a single tube portion. The continuousunit is then cut to obtain the desired lengths of body and legs in theindividual prosthesis units. We have also found that the density of theweaving is increased by applying variable tension to alternate warpfilaments.

With these and other objects and features in view, the nature of whichwill be more .apparent, the invention will be more clearly understood byreference to the drawings, the accompanying detailed description and theappended claims.

In the drawings:

FIG. 1 is a sectional plan view of a tube woven in accordance with thisinvention which will form two Y- tubes when severed at line 12-42;

FIgICi. 2 is a transverse section taken at line 22 on FIG. 3diagrammatically shows the position of yarns in the shed during a pickof the shuttle when weaving at the section of FIG. 2;

FIG. 4 diagrammatically shows the position of yarns in the shed during asubsequent pick of the shuttle when weaving at the section of FIG. 2;

FIG. 5 is a transverse section taken at line 55 on FIG. 1;

FIG. 6 diagrammatically shows the position of yarns in the shed during apick of the shuttle when weaving .at the section of FIG. 5; 40

FIG. 7 diagrammatically shows the position of yarns in the shed duringthe return pick of the shuttle from FIG. 6;

FIG. 8 diagrammatically shows the position of the yarns in the shedduring the subsequent pick of the shuttle from FIG. 7;

FIG. 9 is a transverse section taken at line 9-9 on FIG. 1;

FIG. 10 diagrammatically shows the position of the yarns in the shedduring the picks of an associated pair of shuttles when weaving at thesection of FIG. 9;

FIG. 11 diagrammatically shows the position of yarns during subsequentpicks of the associated pair of shuttles when weaving at the section ofFIG. 9;

FIG. 12- is a diagrammatic end view of a narrow fabric loom showing thepath of warp yarns therethrough and particularly a drop weight systemfor applying tension to the warp;

FIG. 13 diagrammatically shows the path of the filling thread afterweaving the section of FIG. 2;

FIG. 14 diagrammatically shows the path of the filling thread afterweaving the section of FIG. 5; and

FIG. 15 diagrammatically shows the path of the filling thread afterweaving the section of FIG. 9.

Referring to the drawings in detail, this invention as 3 illustrated isembodied in a Y-shaped woven tube for blood vessel replacement havingcommon warp yarns throughout the body and legs and being reinforced atthe point of bifurcation.

As shown in FIG. 1, there is a continuous woven unit 11 which will becut along line 1212 to form two Y-tubes 13, each having a single lumenor body portion 14, double lumen or leg portions 16 and a reinforcedjunction area 17 forming a single-ply fabric, referred to as planarfabric portion in the claims in contrast to the tubular portions 13 and14. The unit 11 can be woven on standard narrow fabric looms, modifiedas hereinafter described, continuously for as long as desired, switchingfrom single to double lumen whenever desired to obtain the desired bodyand leg length.

Tubular ribbon is commonly woven in lIl'bbOIl mills on looms where theshuttle makes a pick in one direction through one ply of fabric and inthe other direction through the associated and other ply of fabric. Inother words, the ribbon is formed flat but of two plies in parallel andadjacent planes. Since the filling thread passes alternatively throughthe two plies, there is an endless fabric or tube, the lumen of whichcan be formed by separating the two plies.

In fact, the body 14 as shown in FIG. 1 is formed in the conventionalmanner which is further understood by reference to FIGS. 2 to 4 whichrepresent sections through a loom shed transverse to, and thus showingthe relative position of, the warp threads during the weaving operation.Line 18 shows the path and direction of the shuttle (and thus thefilling thread) which is always at the same level. In FIG. 3, theshuttle has passed to the right through upper warp thread group 19 whichrepresents the warp threads of the upper ply of the body or single lumentubular portion 14. When the shuttle has reached the righthand position,the loom harness operates to lift the lower warp thread group 21 to theshuttle level (not shown) so that the shuttle returns through lower warpthreads 21 which represent the lower ply of the body.

Both the upper and lower warp groups are further divided into twosub-groups, indicated at 22 and 23 for the upper warp and 24 and 26 forthe lower warp. After the shuttle has returned to the left through lowerwarp threads 21, the loom harness lowers the upper warp threads 19 toshuttle level and also at the same time reverses the relative verticalposition of groups 22 and 23, on the one hand, and 24 and 26 on theother, which is necessary to give a weaving pattern to the fabric. Whileat this position the shuttle passes to the right through the upper warpthreads as shown in FIG. 4. With the shuttle at the right, the loomharness raises the lower warp threads 21 to shuttle level (not shown)with group '26 now spaced above 24 for the return throw of the shuttle.To this point, the operation of the loom in weaving the tubular ribbon(representing body 14) has been conventional.

It is necessary, however, to change to a double lumen arrangement tosecure legs 16. Legs are defined herein as beginning when the body lumendivides into two lurnens. At a predetermined length, the operation ofthe loom harness is changed to that shown in FIGS. to 8 so that theupper warp group 27 has lost a group of threads at the center whichjoined with an associated group of threads from lower warp group 28 toform a fixed warp group 29 which always remains at shuttle level. Thusas shown in FIG. 6, during the shuttles pass to the right through theupper warp threads 27, the fixed warp threads 29 are also at shuttlelevel. In FIG. 7, for the return pass of the shuttle to the left, thelower warp group 28 has been raised to shuttle level but the fixed group29 remained at shuttle level, however, reversing the vertical positionof subgroups 31 and 32 in order to produce a weave pattern. In FIG. 8,on the next shuttle pass to the right the subgroups 33 and 34 of upperwarp group 27 are again at shuttle level but reversed relative to eachother to give a weaving pattern. At the same time, the fixed group 29remains at shuttle level but has again reversed the vertical positionsof subgroups 31 and 32. In other words, groups 31 and 32 remain atshuttle level for every pass but are vertically reversed for eachsuccessive pass. Immediately subsequent to the shuttle pass of FIG. 8,the shuttle will pass to the left but the lower warp group 28 will be atshuttle level wih subgroups 36 and 37 reversed (reversal shown in FIG.8) from their relative positions shown in FIGS. 6 and 7. The fixed group29 will, of course, remain at shuttle level but reversing subgroups 31and 32 from the relative position of FIG. 8 to the same as shown in FIG.7.

The weaving arrangement of FIGS. 6 to 8 is continued for approximatelyeight picks in the preferred embodiment, although it may 'be shorter,longer, or even con tinued indefinitely if there is a desire for adouble lumen tube having an attached single-ply layer between thelumens. In fact, such a double lumen tube could be woven without regardto a single lumen, such as portion 14 or free legs (after cutting) suchas 16. In the embodiment shown in FIG. 1, it will be appreciated,however, that the weaving arrangement just described for a relativelyfew picks leaves a one-ply fabric reinforcing area 17 which will serveto resist both rupture and leakage at this vital area in a blood vesselgraft.

After termination of the reinforcing area, the loom harness operation isagain changed to effect the thread movement shown in FIGS. 9 to 11 and asecond shuttle is brought in operation to pass simultaneously to theright or left with the first one but at a lower plane. Thus as shown,there are now four major groups of thread, namely, the upper left group38 subdivided into groups 39 and 41, the lower left group 42 subdividedinto groups 43 and 44, the upper right group 46 subdivided into groups47 and 48 and the lower right group 49 subdivided into groups 51 and 52.The upper shuttle path 50 is on the same plane as the earlier describedpath 18 and in fact the shuttle is the same. The lower shuttle path 55represents a shuttle just brought into operation that effects a weavingpath to the right and below path 50.

When upper left warp group 38 and upper right warp group 46 are atshuttle levels 50 and 55 respectively, the

two shuttles move to the right as shown in FIG. 10. Subsequently (notshown) the lower left warp group 42 and the lower right warp group 49are lifted by the harness to the associated shuttle levels (groups 38and 46 being simultaneously lifted above shuttle levels similar as upperwarp group 27 in FIG. 7) and the shuttles pass to the left. With bothshuttles at the left, the harness again places the upper left warp group38 and the upper right warp group 46 at shuttle level but subgroups 41and 48 are now respectively on top as seen in FIG. 11 so as to obtain aweaving pattern. Thereafter, the lower left warp group 42 and the lowerright warp group 49 are brought to shuttle level (not shown) withsubgroups 44 and 52, respectively, on top (as shown in FIG. 11). Thustwo independent and separate tubes are being woven at this point butfrom warp threads common to the single tube earlier described. An equaldivision between the two tubes has been shown but an unequal divisioncan be arranged if desired. Furthermore, it is obvious that more thantwo leg members can be woven in integral depending relation to the bodyif desired. When it is desired to return to weaving of the single tubeportion, the procedure described hereinbefore is reversed.

From the foregoing description, it will be apparent that sixteendifferent harnesses are required to control the warp thread movements.Accordingly, the threads for each harness have been shown in a differentcross-hatch design so that the individual threads can easily be tracedthrough the various weaving steps shown in FIGS. 2 to 11. Although onlyone thread has been shown for certain harness groups, it will beappreciated that this is representative of a plurality of threads.

Harness warp threads 53 always appear from the left margin extendingtoward the center on the upper shed level, either above or below theimaginary shuttle path. Harness warp threads 54 appear similarly as 53except that the two groups always appear in interchanging opposition toeach other above or below the imaginary shuttle path. Harness warpthreads 56 and 57 always appear from the left margin extending towardthe center on the lower shed level and in opposition to each other aboveor below the imaginary shuttle path. Harness warp threads 58 and 59always appear from the right margin extending toward the center on theupper shed level and in interchanging opposition to each other above orbelow the imaginary shuttle path.

Although as seen in FIGS. and 11, threads 58 and 59 are below all of thethreads on the left side, it will be appreciated that 58 and 59 arestill in the upper shed relative to the new shuttle path 55. Harnesswarp threads 61 and 62 always appear from the right margin extendingtoward the center on the lower shed level in interchanging opposition toeach other above or below the imaginary shuttle path.

Harness warp threads 63 and 64 which generally appear in interchangingopposition to each other above or below the imaginary shuttle pathappear on the right margin of the upper ply of the left leg in FIGS. 10and 11, toward the center of the upper ply of the main body in FIGS. 3and 4, and toward the left margin of the single reinforcing ply in FIGS.6 to 8. Harness warp threads 66 and 67 generally appear in interchangingopposition to each other above or below the imaginary shuttle path onthe right margin of the lower ply of the left leg in FIGS. 10 and 11,toward the center of the lower ply of the main body in FIGS. 3 and 4,and toward the left margin of the single reinforcing ply in FIGS. 6 to8. Harness warp threads 68 and 69 generally appear in interchangingopposition to each other above or below the imaginary shuttle path onthe left margin of the upper ply of the right leg in FIGS. 10 and 11,toward the center of the upper ply of the main body in FIGS. 3 and 4,and toward the right margin of the reinforcing single ply in FIGS. 6 to8. Harness warp threads 71 and 72 generally appear in interchangingopposition to each other above or below the imaginary shuttle path onthe left margin of the lower ply of the right leg in FIGS. 10 and 11,toward the center of the lower ply of the main body in FIGS. 3 and 4,and toward the right margin of the single reinforcing ply in FIGS. 6 to8.

It is possible and within the scope of the invention to go directly fromthe single lumen weaving of FIGS. 2 to 4 to the double lumen of FIGS. 9to ll without forming reinforced area 17. In such a case there may be asmall opening which can be sealed with adhesive, molten thread material,clotted blood, etc.

The weaving pattern has been shown as a simple oneup-one-down pattern ineither direction and is not considered an important feature.

It is necessary, of course, to secure a tight weave in blood Vessel workand it is preferred to have a higher density than heretofore woven intubular ribbon processes. We have found that a significant andcontributing factor to such a dense weave is providing a differentialpressure or tension to alternative warp threads during the weavingprocess, i.e., every second warp thread going into a particular ply orwall of a tube, will have from about 5 to 30% less tension with about20% being the preferred difference. With this variable tension onadjacent threads, a tighter wall can be woven. This variable tensionfeature is applicable to narrow fabric weaving generally, i.e., singleand double ply, tubular and non-tubular bifurcated and straight, etc.The differential tension may be applied by various means other than thespecific method described hereinafter.

FIG. 12 shows the diagrammatic cross-section of the path of travel offilaments through a ribbon loom 75. The warp spools 73 are placed onpins in the backracks 74 from which the individual threads 76 passupwardly and over the top castle rolls 77 and thence down to the warphanger rolls 78. The thread then again passes upwardly over the topcastle rolls 77 and thence down under the glass rods 79 of the beam. Thethreads then pass through the harness and reeds (not shown) in the shedarea 81 at the end of which the fabric is formed and is then rolled overthe take-up rolls 82.

The differential tension is: applied to adjacent threads by placingdifferent Weights on the carriers 84 provided at the warp hanger rolls78.

For example, the normal tension applied is one pound per ten threads byway of the carriers to all threads but we apply 0.9 pound per tenthreads by weights 83 and 1.1 pounds per ten threads by weights 86 whichis applied to alternate threads between and adjacent the threads undertension of weights 83. The differential weights will be applied andadjusted, of course, so that adjacent warp threads in any given ply offabric in the ribbon are under differential tension. Once thedifferential pressure is applied to the warp threads in the lo-om, nochange is made when weaving the different parts of Y-tubes 13, whichmeans that the reinforced junction area 17 which is a single ply willnot have each adjacent warp thread under different tension as exists inthe other single plies of the tubes. However, it is not important atthat point.

This weaving operation as described may be applied to any type threadbut the specific embodiment here is concerned with unbleached Teflonfilaments of 200 and 400 denier (ail-though denier up to 2,400 feasible)which is preferred in the making of arterial grafts. A dense fabric ispreferred for blood vessel work and approximately 90 warp and 70 fillingthreads are woven per inch in each ply when using 400 denier yarn of 6turns per inch for the warp and 10 turns per inch for the filling. About160 warp and iii-ling threads are woven per inch with 200 denier yarn of10 turns per inch for warp and filling.

It is desirable after weaving of the tube to bleach the Teflon and alsoto corrugate the tubes, both of which may be done by processes not partof this invention.

We claim:

1. An integral woven tubular member formed of warp and filler threadscomprising a pair of longitudinally spaced body tube portions, a pair ofparallel leg tube portions between said body tube portions andinterconnected at their opposite ends to adjacent ends of said body tubeportion, and a planar fabric portion at the juncture of each body tubeportion and the adjacent ends of the pair of leg tube portions all warpthreads extending and being woven throughout the entire length of saidmemher.

2. An integral woven bifurcated blood vessel prosthesis formed of warpand filler threads comprising a body tube, a pair of spaced generallyparallel leg tubes joined to said body tube, said tubes havingconnecting lumens, and a planar fabric portion at the external junctionof said tubes, all warp threads extending and being woven throughout theentire length of said prosthesis.

3. A prosthesis as claimed in claim 2 wherein said planar fabric portionis a single ply having warp threads common to said body and havingfilling thread-s common to said legs.

4. A prosthesis as claimed in claim 3 wherein said planar fabric portionhas approximately eight common filling threads.

5. A prosthesis as claimed in claim 3 wherein said threads are tetrafiuoroethylene resin.

6. -A prosthesis as claimed in claim 5 wherein said threads are fromabout 200 to about 2,400 denier.

7. A prosthesis as claimed in claim 6 wherein said threads are 400denier.

8. A prosthesis as claimed in claim 6 wherein said threads are 200denier.

9. A prosthesis as claimed in claim 2 wherein adjacent warp threads inany tube were under difierent tensions during formation of said tubes,said difference being between 5 and 30%.

10. A prosthesis as claimed in claim 9 wherein said difference isapproximately 20%.

11. A prosthesis as claimed in claim 10 wherein one group of warpthreads were under about 0.09 pound tension per thread and the secondgroup of threads adjacent and between the threads of said one group wereunder ab out 0.11 pound tension per thread.

References Cited in the file of this patent UNITED STATES PATENTS462,040 Fox Oct. 27, 1891 1,157,755 Benjamin Oct. 26, 1915 2,194,038Wallace Mar. 19, 1940 2,250,261 Goldsmith July 22, 1941 2,613,693 JarvisOct. 14, 1952 2,633,574 Dolan Apr. 7, 1953 2,797,712 Shapiro July 2,1957 10 2,924,250 Sidebotham Feb. 9, 1960 OTHER REFERENCES Surgery,published by C. V. Mosby Company, St. Louis, Missouri (1955), Volume 37,pages 167-174.

1. AN INTEGRAL WOVEN TUBULAR MEMBER FORMED OF WARP AND FILLER THREADSCOMPRISING A PAIR OF LONGITUDINALLY SPACED BODY TUBE PORTIONS, A PAIR OFPARALLEL LEG TUBE PORTIONS BETWEEN SAID BODY TUBE PORTIONS ANDINTERCONNECTED AT THEIR OPPOSITE ENDS TO ADJACENT ENDS OF SAID BODY TUBEPORTION, AND A PLANAR FABRIC PORTION AT THE JUNCTURE OF EACH BODY TUBEPORTION AND THE ADJACENT ENDS OF THE PAIR OF LEG TUBE PORTIONS ALL WARPTHREADS EXTENDING AND BEING WOVEN THROUGHOUT THE ENTIRE LENGTH OF SAIDMEMBER.